textproduct: Quad Cities

KEY MESSAGES

- Strong to severe storms are expected this later this afternoon with another round overnight. The Storm Prediction Center has an enhanced, level 3 out 5, risk for severe storms along/north of I-80. South of I-80 a slight, level 2 out of 5, risk for severe storms exist.

- A heat advisory remains in effect through tonight with parts of east central and southeast Iowa, northeast Missouri, and west central Illinois seeing heat indices around 100. - Smoke from Canadian wildfires is forecast to keep hazy skies and poor quality across the area through tonight. Smoke may linger through the day on Tuesday as winds turn more northerly at the surface.

SHORT TERM /THROUGH TONIGHT/

Issued at 149 PM CDT Mon Jul 20 2026

Convection continues to exit into northern Missouri and central Illinois early this afternoon. Clouds are exiting the area from northwest to southeast. An outflow boundary is evident on radar and satellite imagery stretching into Clark County and northwestward toward Ottumwa and Newton. Another area of storms is currently evident on radar and satellite across western Wisconsin into southern Minnesota and far northern Iowa.

Airmass recovery is underway in the wake of earlier convection with areas north of Highway 20 warming into the mid 80s with dewpoints in the mid to upper 70s. This airmass will allow storms currently in southern Minnesota to intensify as they move southeastward. CAMs have shown that this area of storms is expected to intensify with some becoming supercellular as shown with potential intense updraft helicity swaths across the area. This is supported by model soundings as well as hodographs which show strong curvature at least in the 0 to 3 km layer. Additionally, if these storms anchor on the expected retreating outflow boundary from earlier storms, this will lead to increased tornado risk with the potential for strong tornadoes. Additionally, these storms will be capable of large hail damaging winds. Think that the primary threat for severe weather will be from 4 PM to 10 PM. Heavy rain and localized flash flooding will also be possible with PWATs near 2.00 inches.

For later tonight, an unusually strong 500 mb trough and associated 125 knot jet streak will dig into the area tonight. This forcing for ascent is unusually strong for late July and will lead to another round of storm development this evening that will sink southward across the area. The main question is how much instability will this increasing lift have to work with across the area. This could at least lead to rain developing across the area with thunderstorms possible and potentially severe if any instability remains. The potential is there for damaging wind gusts as well as heavy rain overnight although lower instability will lead to more isolated severe potential.

Model consensus has the cool front exiting the area by 12 UTC on Tuesday. The HRRR surface smoke and RRFS show some smoke moving into the area behind the front for Tuesday but with lower concentrations than on Sunday and today.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 149 PM CDT Mon Jul 20 2026

Tuesday onward, the 500 MB pattern will yield troughing in the Great Lakes and Ridging across the western CONUS through the reminder of the week. Little has changed in the forecast thinking from the previous shift. Therefore the previous long term is included below.

Tuesday through Thursday...some lingering early morning showers or storms are possible in the far south as the cold front moves into southern Missouri. Humid conditions will be seen Tuesday until a secondary front moves through. Once this front moves through much less humid conditions and cooler temperatures will be seen Wednesday and Thursday.

Thursday night/Friday Assessment...low (<25%) confidence on rain chances

The model consensus is narrowing the time frame for rain to late Thursday night into Friday morning. Rain chances have increased slightly (20-35%) mainly south of I-80 but this appears to be an anomaly tied to one specific model.

The weak low and associated fronts are progged to be across Missouri so the better rain chances will be associated with the higher moisture and stronger forcing. Indeed, a dprog/Dt of the various models shows a southward shift to the moisture/wind convergence; closer to the frontal boundary. This adds support that the uptick in rain chances is an anomaly. I suspect rain chances will slowly decrease as the week progresses.

Friday night through Sunday Assessment...a certainty (>98%) of slowly rising humidity levels

All models show southerly flow redeveloping over next weekend as the heat dome builds north in the Plains. Dew points in the 50s Friday night will slowly climb into the low to mid 60s Saturday with mid to upper 60s dew points by Sunday. The increasing temperatures and moisture will slowly push heat indices into the 90s by Sunday.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1241 PM CDT Mon Jul 20 2026

A line of storms and trailing light rain continues to exit KMLI and KBRL early this afternoon with MVFR to IFR ceilings and visibilities. This line of storms and precipitation is expected to clear KBRL and KMLI by 19 UTC. KCID and KDBQ continue to have MVFR visibilities in smoke. Isolated showers are possible through 00 UTC but confidence is low on the timing at each TAF site so continued to use the prob 30 groups. Another line of storms is forecast to move across the area between 02 and 08 UTC along a cool front with MVFR to IFR ceilings and visibilities across the area in storms. Rain showers may linger after 06 UTC but VFR conditions are expected to prevail after 12 UTC with gusts northwest winds.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory until 8 PM CDT this evening for IAZ051-063- 076>078-087>089-098-099. IL...Heat Advisory until 8 PM CDT this evening for ILZ025-034. Air Quality Alert until midnight CDT tonight for ILZ001-002- 007-009-015>018-024>026-034-035. MO...Heat Advisory until 8 PM CDT this evening for MOZ009-010.